package s_3

import (
	"fmt"
	"sync"
)

var m *Manager
var lock *sync.Mutex = &sync.Mutex{}

func GetInstance() *Manager {
	if m == nil {
		lock.Lock()
		defer lock.Unlock()
		if m == nil {
			m = &Manager{}
		}
	}
	return m
}

type Manager struct {
}

func (p Manager) Manage() {
	fmt.Println("manage...")
}
